So, I have a 29 gallon tank (18" tall) with a run-of-the-mill 17 W T8 full-spectrum bulb. (The attached photo is slightly overexposed and the lighting is a little more subdued than it appears. Outside of the hair algae growing on the Hornwort at the top, I have very little growing elsewhere in the tank.) When the lights are off early in the morning, my Black Neon and Cardinal Tetras are swimming about near the top of the tank, and my Rummys shoal out in the open. The second that the lights go on, everybody hunkers down into the lower half of the tank and the Rummys tend to stay within the plants. It's not until early afternoon that my tetras loosen up and swim higher and more freely (not coincidentally, late afternoon is feeding time).

So it seems to me that even this relatively dim lighting is stressing them a bit. I've tried to combat this by tethering Hornwort to the top of the right side of the tank, and the Rummys especially seem to appreciate this. I also have five pieces of driftwood that leach tannins into the water and give it a peaty tinge.

Is there a dimmer light that I can use, while still keeping my plants alive? I'm open to using LEDs. Plants are mostly low-light species such as Java Fern, Crypt spiralis, Crypt wendtii, and Staurogyne repens. (The latter is marginal in my current lighting, but I'm not particularly attached to it.)